Technical Field
This disclosure generally relates to the automatic control of watercraft propulsion components, and in particular, to automatic systems and methods for protecting watercraft motor legs and propellers using depth sensor information.
Related Art
Many powered watercraft today utilize one of three well known types of motor/propulsion or drive arrangements: “inboard,” “outboard,” and “inboard/outboard” (“I/O”) or so-called “sterndrive” arrangements. Each of these has associated advantages and disadvantages and differs from the others primarily in the location of the motors or engines that drive them and the arrangements by which the motors are coupled to a screw or propeller used to propel the watercraft over the surface of a body of water. However, all three inherently have the common feature that the propeller and at least a portion of the drive shaft and/or motor “leg,” to which the propeller is drivingly coupled are disposed below the water surface and are therefore subject to damage if they collide with the sea bed or a submerged object as the watercraft travels over the water.
All drive types may include a “shear pin” or “slip clutch” arrangement that couples the propeller to the associated drive shaft or leg to provide some measure of protection for the propeller, and which function by breaking or slipping when a blade of the spinning propeller impacts a solid object with sufficient force, thereby enabling the drive shaft to spin independently of the propeller. Outboard drives and I/O or sterndrives also typically include an arrangement that allows the lower end of the motor leg and propeller to “kick up,” i.e., pivot upwardly and rearwardly relative to the watercraft upon their impact with a submerged object or the floor of the body of water. Since inboard drives lack motor legs, they also lack this latter protection scheme. However, regardless of the drive type, any use of these conventional protective measures typically results in at least a measure of inconvenience for the watercraft's owner and are often inadequate to prevent expensive damage to the propeller, the drive leg, the watercraft's keel, and/or other submerged components of the watercraft.
What is needed then is an automated system that functions to protect watercraft propellers and the legs of outboards and sterndrives from damaging contact with the floor of the body of water in which the watercraft floats, and that enables shallow running without the need for constant manual trim adjustments. Further, it would be desirable to provide a system that, when beaching the watercraft, automatically lifts and/or tilts the outboard or sterndrive leg at a rate corresponding to the sea bed incline, and further, automatically retracts any “trim tabs” used to raise/lower the stern of the watercraft, and/or any other adjustable watercraft components, in order to protect them from damage.